content: /*
   * Copyright 2011-2016 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package ix;
  
  import java.util.*;
  
  final class IxIntersect<T> extends IxSource<T, T> {
  
      final Iterable<? extends T> other;
  
      IxIntersect(Iterable<T> source, Iterable<? extends T> other) {
          super(source);
          this.other = other;
      }
  
      @Override
      public Iterator<T> iterator() {
          return new IntersectIterator<T>(source.iterator(), other.iterator());
      }
  
      static final class IntersectIterator<T> extends IxSourceIterator<T, T> {
          final Iterator<? extends T> other;
  
          final Set<T> set;
  
          boolean once;
  
          IntersectIterator(Iterator<T> it, Iterator<? extends T> other) {
              super(it);
              this.other = other;
              this.set = new HashSet<T>();
          }
  
          @Override
          protected boolean moveNext() {
              Set<T> secondSet = set;
              if (!once) {
                  once = true;
                  Iterator<? extends T> o = other;
                  while (o.hasNext()) {
                      secondSet.add(o.next());
                  }
              }
  
              Iterator<T> fIt = it;
              while (fIt.hasNext()) {
                  T v = fIt.next();
  
                  if (secondSet.contains(v)) {
                      value = v;
                      hasValue = true;
                      return true;
                  }
              }
  
              done = true;
              return false;
          }
      }
  }
  